I have four rigs that all have 5 x 5870s running at 950/180 clocks and providing 2200mhash (approx) per rig

that cooler master power supply should work no problem as long as its 80 plus certify (yes I am sure numerous people are going to tell you 80 plus does not matter but my experience has proven that to be a myth)

I use 1000watt corsair 80 plus bronze PSUs on all my rigs with 5870s - it works just fine plenty of power, only thing is I assume your going to be using extender cables make sure at least one of them is powered with the molex connector so your not trying to pull too much power from the MB

The max wattage I saw when running my 5 5870s at 950/150 1.150v was 980 watts, so that won't leave much wiggle room. Personally, i run off a Seasonic 1250W PSU, which I know are rated for 100% continuous capacity. I do not know how Cooler Masters stack up, but I hear they are pretty good, still don't think i would run one at 100% full time though.

The max wattage I saw when running my 5 5870s at 950/150 1.150v was 980 watts, so that won't leave much wiggle room. Personally, i run off a Seasonic 1250W PSU, which I know are rated for 100% continuous capacity. I do not know how Cooler Masters stack up, but I hear they are pretty good, still don't think i would run one at 100% full time though.

you can speculate if it will work or not all you want but I can tell you from EXPERIENCE

I am currently running 4 rigs with 5 x 5870 and 1000watt PSUs and have been doing so for almost a YEAR

believe me it works, if that coolermaster is 80plus it will have no problem just make sure you have an least one powered extender

I run 6x 5870 all Powercolor's OC editions @ 960/300 on a TAGAN 1300W 2Force II PSU (absolutely 0 certs but only 500CNY) which unfortunately is split into a ton of rails leaving 1180W for 12v but it has run nicely since May last year. And all I've done is turn the CPU way down.